New micro-pump technology may offer promising alternative to eye drops for glaucoma patients

It is no secret that the issues associated with current glaucoma medications can be problematic. Systemic medications carry the risk of side effects, while the current medical treatment of choice, eye drops, has its own drawbacks. Studies show that half of patients stop taking their prescription glaucoma eye drops after a year, leaving them vulnerable to vision loss.

There are a variety of reasons for this, including forgetfulness, physical limitations like arthritis, the discomfort of the drops themselves, even frustration arising from having much of the medication run down the patient's cheek instead of staying in their eye. On a national scale, the annual cost of this noncompliance in both direct and indirect medical expenses is almost $300 billion. It is a daunting problem, but the folks at the Roski Eye Institute came up with a possible answer.

The Research
To deal with these issues, a research team led by Dr. Mark S. Humayun at the University of Southern California's Roski Eye Institute, part of the university's Keck School of Medicine in Los Angeles, took a novel approach. They developed a pump that could be implanted directly into the eye. Medication is injected into a reservoir through a port and the dosage and frequency are controlled by a wireless device.

Eleven subjects with Diabetic Macular Edema, a chronic blinding disease treated with medication, and visual acuity of logMAR 0.30 (20/40 eyesight) or worse were included in the initial study. After implantation, the device was wirelessly programmed to deliver the predetermined dosage of the DME drug ranibizumab. The subjects then received comprehensive ophthalmic examinations as well as optical coherence tomography biweekly for the next 90 days, at which time the device was removed. The subjects then received standard care.

The Results
There were seven successful trials and four unsuccessful trials. In the successful ones, the micropump delivered the dose to within 20% of the target amount. These subjects saw improved visual acuity and retinal thickness, enough to be deemed successful. Of the four unsuccessful trials, the dosage delivery was too slow or inhibited by a damaged device. In spite of this, the results were considered promising. There were no serious adverse effects, all of the subjects healed normally, and no one complained of feeling the pump in their eye. Improvements to the device were approved for the next study.

The Future
The micropump technology is being commercially developed by Pasadena, California-based Replenish, Inc., which was founded in 2007 for the express purpose of bringing this technology to the marketplace. Since 2009, the company has raised more than $20 million from investors to develop the technology through pre-clinical and clinical trials, which has helped this micropump technology to come as far as it has.

That's exactly what Glaucoma Research Foundation is looking for: Support for researchers working to put an end to progressive vision loss from glaucoma. See how you can help today.